1. Field of the Invention
The present invention relates to a multi-band radio frequency (RF) receiving method and apparatus in a mobile communication system. More particularly, the present invention relates to an RF receiving method and apparatus capable of simultaneously receiving two frequency bands among a plurality of received frequency bands and capable of reducing numbers of RF filters and local oscillators required for converting an RF wave signal into an intermediate frequency (IF) signal, thereby remarkably reducing system size and cost.
2. Description of the Related Art
Recently, as wireless portable terminals have become miniaturized and lightweight, and fabrication and architecture technologies of semiconductors have advanced, there has been an increasing demand for integrating various components for mobile communications into a single chip to minimize space occupied by the components. According to such a tendency of one-chip component integration, RF receiving apparatuses are also integrated into one-chip components in view of a low-noise amplifier, mixer or local oscillator. However, since it is very difficult to implement an on-chip RF filter having adequate characteristics by existing technology, the RF filter is mounted on an RF receiving apparatus in an off-chip type.
The RF filter is used to select a frequency signal corresponding to each band in an RF receiving apparatus for a wireless portable terminal. The RF filter includes a first filter and a second filter. The first filter receives a desired frequency band signal from a plurality of frequency band signals received via an antenna, and removes unnecessary signal components to prevent saturation of a low-noise amplifier. The second filter removes unnecessary signal components such as image components.
As described above, the module size and cost of an RF receiving apparatus are mostly attributed to the RF filters mounted as off-chip discrete components. Thus, in order to realize a miniaturized, low-cost module, it is necessary to reduce the required number of RF filters while maintaining the same level of RF filtering performance.